Japan is celebrating the return home of troops after two-and-a-half years in Iraq without a single casualty. The controversial mission was seen as a test of Japan's long policy of pacifism.

Japanese leaders gathered Saturday to formally welcome home the country's first troops deployed to a combat zone since World War II.

Prime Minister Junichiro Koizumi expressed relief that the hundreds of members of the Ground Self Defense Force executed their humanitarian mission in Iraq without suffering any combat-related casualties.

Mr. Koizumi says the troops did a wonderful job under difficult circumstances. He says their efforts were highly praised by the Iraqi government and people.

The troops helped build schools, roads and dispensed clean water in the relatively peaceful and sparsely populated Samawah area. They were dependent on Dutch, Australian and British forces for security.

Although the Japanese forces shied away from combat operations, the deployment was a watershed in Japan's post-World War II. Government leaders, including the prime minister, say they expect its success will clear the way for more overseas missions, including a return to Iraq if the security situation improves there.

The deployment was also seen as testing the limits of Japan's pacifist constitution, imposed by the United States occupation following World War II.

Prime Minister Koizumi saw the mission as a way to show support for the United States and the war on terrorism. Many Japanese, however, opposed it, either because they were against the war in Iraq or because they believed the mission violated the constitution.

Japan still maintains a presence in the Middle East with an air operation in Kuwait that ferries United Nations and coalition personnel and supplies into Iraq.